1. Field of the Invention
This invention relates to a television set, its cabinet, and a metal mold for the cabinet.
2. Description of the Prior Art
The conventional TV cabinet has structure as shown in FIG. 6.
FIG. 6 is an illustration of the configuration of the upper left corner of the back of the front plate of a conventional TV cabinet 1. The front plate of the TV cabinet 1 has a rectangular aperture 2. When a CRT is set in the TV cabinet 1, the fluorescent screen of the CRT faces ahead of the TV cabinet 1 through the aperture 2. In FIG. 6, numeral 3 is a boss to support the upper left corner (as seen from behind the CRT) of the CRT. Numeral 4 is a hollow gas channel extending through the base of the boss 3.
Resin is injected into the mold to form the case of the TV cabinet 1. While the case is cooling down, gas pressure is applied to the back of the case to prevent it from deforming or warping.
The gas channel 4 is used to apply the gas pressure to the back of the case of the TV cabinet 1. A zone, through which the gas channel 4 is to be made, is formed thicker than the average thickness of the case. When high-pressure gas is injected into the mold, it makes its way through the channel-forming zone to form the gas channel 4, because the inner portion of the thick channel-forming zone is slow in solidifying and hence still soft. Thus, gas pressure is applied to the back of the case to restrain it from deforming or warping.
However, in the previously described conventional TV, because the gas channel 4 extends through the bases of bosses 3 with longitudinal screw holes 3a, the gas channel 4 may expand and deform or warp the bottom portions of longitudinal screw holes 3a as shown in FIG. 7, causing the trouble that screws cannot properly be screwed into the screw holes 3a when a display is set in the cabinet.
In accordance with the above, it is the object of the present invention to provide a television set, its cabinet, and a metal mold for the cabinet which allow screws to be properly screwed into the screw holes of display-supporting bosses of the cabinet when a display such as a CRT is set in the cabinet.
To achieve the above object, the present invention provides a television set including a resin cabinet, which includes a case, display-supporting bosses, and a hollow gas channel in the neighborhoods of the bosses, all formed in one piece. The case has a front plate, and a rectangular aperture is made in the front plate. When a display is set in the case, its screen faces ahead of the cabinet through the rectangular aperture. The front plate of the case is formed thick in the neighborhood of each corner of the rectangular aperture. Formed erect on the back of the front plate in the neighborhood of each corner of the rectangular aperture is one of the display-supporting bosses. Each boss has a screw hole made along its longitudinal center axis. The gas channel includes a main channel, subchannels, and choke channels. The main channel is formed off the bosses and has gas-injecting spots. Extending under each boss is one of the subchannels, which is connected to the main channel by one of the choke channels. Recesses are made at small intervals in the back of the front plate, on both sides of the channel-forming zone, in the neighborhood of each corner of the rectangular aperture.
As described above, the present invention provides a television set with a cabinet which allows screws to be properly screwed into the screw holes of display-supporting bosses of the cabinet when a display is set in the cabinet.
The gas channel is provided to restrain the front plate of the case from deforming or warping while the case is cooling down in the mold. Namely, while the case is cooling down after resin is injected into the mold, high-pressure gas is injected into the mold to apply gas pressure to the front plate from its back. Accordingly, the front plate cools down under the gas pressure and thereby is restrained from deforming or warping.
The above gas channel is formed by high-pressure gas injected into the mold after the injection of resin. Namely, the mold is so shaped that a solid (not hollow) zone through which the gas channel is to be made will be formed thicker than the average thickness of the front plate of the case. Accordingly, the temperature of the channel-forming zone decreases more slowly than the temperature of the other portions of the front plate. Therefore, when the surfaces of the channel-forming zone in contact with the inner surfaces of the mold and the other portions of the front plate have solidified, the inner portion of the channel-forming zone has not solidified yet. The channel-forming zone includes a main zone, subzones, and choke zones.
At that moment, high-pressure gas is injected into the gas-injecting spots. Because the inner portion of the channel-forming zone is still soft, the high-pressure gas makes its way through the main zone of the channel-forming zone, forming the main channel.
Then, the high-pressure gas reaches the subzones and makes its way into them to form the subchannels.
The portions between the main zone and the subzones are the choke zones; therefore, the high-pressure gas makes its way through the choke zones, too, forming the choke channels.
The choke zones are thinner and narrower than the main zone and subzones; accordingly, the sectional area of the inner soft portion of the choke zone is smaller than those of the main zone and the subzone. Therefore, the choke channel is formed, given a smaller diameter than those of the main channel and the subchannel. Accordingly, the flow rate of the high-pressure gas from the main channel to the subchannel is reduced by the choke channel, which results in a lower gas pressure in the subchannel than the gas pressure in the main channel.
Thus, even if the above subchannel passes under the bottom portion of the display-supporting boss, the pressure of the high-pressure gas is reduced to such a degree that the high-pressure gas does not expand the diameter of the subchannel excessively to deform or warp the bottom portion of the screw hole of the boss.
The front plate of the case are formed thick in the neighborhood of each corner of the rectangular aperture to give the case sufficient strength; accordingly, the high-pressure gas may stray from the channel-forming zone in the neighborhood of each corner of the rectangular aperture. To prevent this from happening, in a cabinet of the invention, the recesses are made at small intervals in the back of the front plate, on both sides of the channel-forming zone, in the neighborhood of each corner of the rectangular aperture. Accordingly, even when the high-pressure gas strays from the channel-forming zone and tries to flow into the thick portions, it cannot form a gas channel because of the recesses. These recesses accelerate the solidification of recessed areas; therefore, although thick portions are provided in the case, the gas channel is formed through only the channel-forming zone.
In the above invention, the cabinet with particular configuration provided in the television set has been described. However, any configuration is acceptable provided that it can be formed by blow molding while restraining the screw holes of display-supporting bosses from deforming. From this aspect, it is possible to provide a cabinet of the invention in a broader sense.
The second aspect of the present invention provides a TV cabinet, which includes a case, display-supporting bosses, and a gas channel in the neighborhoods of the bosses, all formed in one piece. The gas channel includes a main channel, subchannels, and choke channels. The main channel is formed off the bosses and has gas-injecting spots. Extending under each boss is one of the subchannels, which is connected to the main channel by one of the choke channels.
According to the second aspect of the present invention, the screw holes of bosses to support any components in a television set can be restrained from deforming. Besides, the formation of the gas channel is not limited to a thick zone. If the gas channel is to be formed through a zone of the average thickness or a thin zone, it can be formed without providing thin portions, or recesses, on both sides of the zone.
Thus, the second aspect of the present invention provides a TV cabinet which allows screws to be properly screwed into the screw holes of display-supporting bosses when a display is set in the TV cabinet.
An example of the TV cabinet has thin portions on both sides of the channel-forming zone.
Namely, if the gas channel is to be formed through a thick zone of the case, it can be accomplished by providing thin portions on both sides of the thick zone.
Thus, according to the second aspect of the present invention, the gas channel is formed without its straying from the desired course.
Another example of the TV cabinet will follow. The case of the TV cabinet has a front plate. A rectangular aperture is made in the front plate. When a display is secured to the front plate, its screen faces ahead of the TV cabinet through the rectangular aperture. The front plate is formed thick in the neighborhood of each corner of the rectangular aperture. One of the display-supporting bosses is formed erect in the back of the front plate in the neighborhood of each corner of the rectangular aperture. Each boss has a screw hole made along its longitudinal center axis. Recesses are made at small intervals on both sides of the channel-forming zone in the neighborhood of each corner of the rectangular aperture.
Namely, the second aspect of the present invention is applicable to the front section of the cabinet of the television set of the first aspect in order to restrain the screw holes of display-supporting bosses from deforming.
Thus, according to this aspect of the invention, it becomes possible to restrain the screw holes of display-supporting bosses from deforming.
The third aspect of the present invention provides a metal mold to form the TV cabinet of the second aspect. An example of the metal mold includes (i) a mold surface to form a case, display-supporting bosses, and a channel-forming zone in the neighborhoods of the bosses, all in one piece, (ii) resin injection holes to inject resin into the mold, and (iii) gas injection holes to inject high-pressure gas into the mold. The case has a front plate, wherein a rectangular aperture is made. Formed in the neighborhood of each corner of the rectangular aperture is one of the bosses. The channel-forming zone includes a main zone, subzones, and choke zones. The main zone is thick and off the bosses and has gas-injecting spots overlapping the gas injection holes. Formed in the neighborhood of each corner of the rectangular aperture is one of the subzones, which is thick, extends under the boss in the neighborhood, and is connected to the main zone. Also formed in the neighborhood of each corner of the rectangular aperture is one of the choke zones, which is thinner and narrower than the main zone and connects the subzone in the neighborhood to the main zone.
Thus, the present invention can be embodied as a mold to form the TV cabinet of the second aspect of the present invention, too.
As described above, the third aspect of the present invention provides a mold to form a TV cabinet which allows screws to be properly screwed into display-supporting bosses when a display is set in the TV cabinet.
The mold surface of the above example of the metal mold may be so shaped that the neighborhood of each of the display-supporting bosses will be formed thick and recesses will be formed at small intervals on both sides of the channel-forming zone.
Namely, a gas channel can be formed without its straying from a desired course by contriving the pattern of the mold.
As described above, the third aspect of the present invention enables the formation of a gas channel through only a desired course.